Abstract
The recrystallization behaviors of two aluminum-killed steels were investigated in isothermal annealing and continuous heating, starting with either as hot-rolled (as taken from productional hot strip coils) or as cold-rolled (ca. 70%).
Careful electron microscopy (carbon extraction replica), run along with the measurement of solute nitrogen by internal friction method, revealed that, even when no evidence of A1N precipitation is apparent, there is definitely some precipitation of AIN of almost sub-electron microscopic sizes. The electron diffraction pattern of those minute A1N precipitates did not conform to that of hexagonal A1N, but fit very well with that of a hypothetical cubic A1N of NaCl type structure with (a)=4.047Å.
It was seen that the recrystallized textures were closely related to the state of the cubic A1N precipitation;(1) when the recrystallization began after the precipitation of cubic AIN had progressed to certain extent, in the unrecrystallized region, strong texture with {554}‹225› and {111}‹011› as its major components resulted, (2) when the precipitation of cubic A1N proceeded concurrently with recrystallization, very strong texture with {111}‹011› as its major component resulted, and (3) when the recrystallization had been completed before the precipitation of cubic A1N, the texture was weak, being similar to that of rimmed steel sheets.
